Characterization of Superconducting Thin Films Using a Generic Property of Resonators

Abstract

A complete characterization of high-temperature superconducting films, as a function of microwave power, must track changes of the surface resistance and the penetration depth. A key problem has always been tracking power-dependent nonlinearities associated with a change in penetration depth. In this paper, we report a technique which exploits the generic response of resonators to a microwave impulse. We show that a transient response is observed which has a frequency equal to the difference between the driving frequency and the resonant frequency of the resonator. Moreover, we demonstrate how this transient response can be used to determine the nonlinear properties of superconducting thin films.